THE EFFECT OF MICROWAVE IRRADIATION ON THE MECHANICAL PROPERTIES OF KIMBERLITE AND LIMESTONE

Abstract

THE EFFECT OF MICROWAVE IRRADIATION ON THE MECHANICAL PROPERTIES OF KIMBERLITE AND LIMESTONE

Abstract

In underground excavation, rock fragmentation can be achieved by blasting with explosive materials or using continuous excavation machinery. The significant challenges with the explosives include noise, vibration, pollution, and potential issues such as damage to nearby structures. A less disruptive method for breaking rocks is using machines such as tunnel boring machine and road header those have the capability of continuous operation and are suitable for autonomous mining. In hard rock applications, the excavation machinery is associated with high equipment wear rates, low penetration rates and consequently high operating costs. This paper investigates the work being undertaken at McGill University on the effect of microwave (MW) irradiation on hard rocks to facilitate continuous mining and improve the production rate while reducing costs. Tuffistic Kimberlite (TK) and limestone rocks were studied in this research. Physical properties of untreated samples were measured, and the rock samples were treated for various exposure times in a multi-mode MW unit at power levels ranging from 2 to 10 kW. The results indicate that MW irradiation reduced the strength of TK and limestone rocks. It was concluded that Brazilian Tensile Strength (BTS) and Uniaxial Compressive Strength (UCS) of samples decayed proportionally with exposure time and power level.

Keywords: Kimberlite, Microwave Irradiation, Fragmentation, Mechanical Strength, Rock Excavation